[PATCH 02/11] rcu: Allow rcu_user_enter()/exit() to nest

Allow calls to rcu_user_enter() even if we are already in userspace (as seen by RCU) and allow calls to rcu_user_exit() even if we are already in the kernel. This makes the APIs more flexible to be called from architectures. Exception entries for example won't need to know if they come from

[PATCH 02/11] rcu: Allow rcu_user_enter()/exit() to nest

Allow calls to rcu_user_enter() even if we are already in userspace (as seen by RCU) and allow calls to rcu_user_exit() even if we are already in the kernel. This makes the APIs more flexible to be called from architectures. Exception entries for example won't need to know if they come from